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Optical Tweezers
Published in Klaus D. Sattler, st Century Nanoscience – A Handbook, 2020
Although the number of reported experiments and theories about Janus particles in optical tweezers has increased steadily, the field is still relatively unexplored. However, accurate calculations about optical and thermophoresis forces exerted on Janus particles still face intractable problems, due to the drastic contrast in space scale for optically distinct different metal and dielectric materials. Continuous developments in computational electromagnetics simulations will improve this situation and may give possibilities for the detailed dynamic process of Janus particles in various optical traps. Last but not least, with the advantage of amphipathic property, the compound Janus particles can promote magnificent prospects in diverse areas of high current interest, including targeted drug delivery, light-driven micromachines, self-assembly of particles [47–50], and more.
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Published in Luis Liz-Marzán, Colloidal Synthesis of Plasmonic Nanometals, 2020
Denis Rodríguez-Fernández, Luis M. Liz-Marzán
In this section we discuss selected general synthetic procedures for the preparation of Janus and patchy particles. Although the focus is on metallic Janus particles (containing at least one metal in the zero oxidation state), we highlight recent papers on the synthesis of non-metallic particles that we consider particularly relevant. For a deep discussion of this topic, we refer the reader to recent reviews.[7–9] In general, the preparation of Janus particles can be summarized in (but not limited to) three general approaches: phase separation, masking and self-assembly.[7] The first method mainly involves the preparation of polymeric Janus particles through emulsion polymerization, seeded growth and microfluidics.[11–16] Masking processes are based on the partial protection of preformed particles by adsorbing them onto either a flat substrate, a larger particle or an emulsion droplet, so that the exposed surface can be further functionalized while maintaining the protected side unchanged.[17–20] Self-assembly techniques entail the organization of block copolymers in solution or a mixture of incompatible ligands at the particle surface.[21,22]
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Published in Chad A. Mirkin, Spherical Nucleic Acids, 2020
Oliver G. Hayes, Janet R. McMillan, Byeongdu Lee, Chad A. Mirkin
The surface ligands of a nanoparticle play a central role in determining its physical and chemical properties, the interactions through which it can engage, and thereby its potential applications [1−4]. Introducing two or more types of surface ligands, at distinct regions on a particle’s surface, for example, in the form of a Janus particle, can yield a structure with a combination of chemical and/or physical properties [5]. The complex architectures and unique characteristics of Janus particles make them useful for a wide range of applications such as emulsion stabilizers [6], sensors [7], therapeutics [8], and components of complex self-assembled materials [9−11]. With two distinct ligand domains, Janus nanoparticles present the opportunity to study colloidal crystallization as a function of orthogonal, directional interactions.
Gemini surfactant based-organomontmorillonites: preparation, characterization and application in pickering emulsion
Published in Journal of Dispersion Science and Technology, 2022
Khadidja Taleb, Salima Saidi-Besbes, Isabelle Pillin, Yves Grohens
A wide variety of soft and rigid particles have been used for emulsion stabilization, including silica,[11,12] cellulose particles,[13] organoclays,[6] carbon black,[14] Janus particles,[15] and graphene oxide.[16] The effectiveness of solid particles for the stabilization of emulsions depends on several factors such as particles nature, shape, wettability and content, oil nature, phase volume fraction, pH and ionic strength.[17,18] The combination of different solid particles [19] or solid particles with surfactants[20] has been also investigated and showed improved emulsion stabilization behavior.[21]
Freezing of a soft-core fluid in a one-dimensional potential: appearance of a locked smectic phase
Published in Molecular Physics, 2021
Alexander Kraft, Sabine H. L. Klapp
It is well established that the presence of structured surfaces can have a profound impact on the phase behaviour and particularly, the freezing transition of atomic, molecular, and colloidal fluids. Typical effects are shifts of the freezing transition with respect to the corresponding bulk transition [1], and a significant impact on the fluid's structure close to the walls [2,3]. Examples include water at the inner surfaces of silica nanopores [4,5] or at graphene sheets [6], atoms between the structured surfaces of a surface force apparatus [7], but also wetting of crystalline phases of colloids close to patterned substrates [8] and active Janus particles at chemically decorated surfaces [9]. In some (yet not all) cases, structured surfaces actually assist the adjacent fluid in developing a solid-like structure, that is, freezing is supported (relative to the bulk system) rather than suppressed.
An overview on synthesis procedures of nanoparticles applied to enhanced oil recovery
Published in Petroleum Science and Technology, 2022
Mariana Schneider, Júlia da Silveira Salla, Rafael Peralta Muniz Moreira, Regina de Fatima Peralta Muniz Moreira
This method is based on a particle-stabilized emulsion and is considered a versatile method for synthesizing a large quantity of Janus particles with control of the geometry and size (Jiang et al. 2010), as represented in Figure 3 and summarized in Table 6.